BLOOD VESSELS

ARTERIES FUNCTION – CARRIES OXYGENATED BLOOD AWAY FROM THE HEART EXCEPTION: PULMONARY ARTERY – CARRIES DEOXYGENATED BLOOD AWAY FROM HEART TO LUNGS MADE OF LAYERS OF SMOOTH MUSCLES AND CONNECTIVE TISSUE (COLLAGEN, ELASTIC FIBERS)

ARTERIES HIGH BLOOD PRESSURE, THICKNESS TO SEND BLOOD THROUGHOUT THE BODY DEEPLY LOCATED IN BODY EXAMPLES – CORONARY (heart), AORTA (main artery out of heart), CAROTID (neck  brain), FEMORAL (thigh)

ATHEROSCLEROSIS

CEREBRAL ARTERIES IN BRAIN

VEINS FUNCTION – CARRIES DEOXYGENATED BLOOD TOWARDS THE HEART EXCEPTION: PULMONARY VEIN – CARRIES OXYGENATED BLOOD FROM LUNGS TOWARD HEART THINNER WALLS WITH LOWER PRESSURE NECK + LIMBS HAVE TWO SETS OF VEINS: DEEP AND SUPERFICIAL  OFTEN USED TO REGULATE BODY TEMPERATURE AND DRAW BLOOD ETC.

VEINS TO ALLOW BLOOD FLOW TO OPPOSE THE FORCE OF GRAVITY AND PREVENT BACKFLOW, VEINS CONTAIN ONE-WAY VALVES FORMED FROM FOLDINGS OF INNER CONNECTIVE TISSUE SURROUNDING SKELETAL MUSCLE CONTRACTIONS ALSO HELP PUSH BLOOD UP TOWARDS THE HEART

VEINS EXAMPLES – SUPERIOR & INFERIOR VENA CAVA (main vessels back to heart), JUGULAR (neck)

$$ in the BANK VASOCONSTRICTION: making diameter of blood vessels smaller  LESS blood flow, HIGHER blood pressure VASODILATION: making diameter of blood vessels larger  MORE blood flow, LOWER blood pressure Change due to body temperature, hormones, carbon dioxide/oxygen levels etc.

Blood is warmer than the body and can help regulate body temperature Blood vessels dilated superficially easily lose heat

CAPILLARIES FUNCTION – WHERE MATERIALS (OXYGEN, WATER, CARBON DIOXIDE, GLUCOSE) ARE EXCHANGED BETWEEN BLOOD AND TISSUE (SKELETAL MUSCLE, ORGAN, BRAIN ETC.) VERY SMALL IN DIAMETER  WALLS ARE ONLY ONE CELL THICK!

CAPILLARIES DIFFUSION TAKES PLACE TO EXCHANGE GASES (high  low concentration), OSMOSIS FOR WATER, ACTIVE TRANSPORT OF OTHER MATERIALS INTO CELLS LARGE NETWORK  “CAPILLARY BED”

CAPILLARY BED